Clarification about annihilation in Tenet

Question

This is about the concept of annihilation in Tenet.

The concept of inverting oneself is introduced. When an individual is inverted, this person will experience the flow of time in the reverse direction. In one of the scenes, the Protagonist is about to get the "Plutonium" from Sator, and a female scientist warns him that he should not contact his forward self. Otherwise, he will be annihilated.

Further on in the movie, the Protagonist travels back to Freeport to un-invert himself where he gets into a scuffle with his forward self. Did this not count as a contact? Why was the Protagonist not annihilated?

Answer 1

When the cavalry Niel called shows up in Tallinn and secures the turnstile after the Protagonist has completed the forward half of the chase, the commander—Ives—tells his deputy—Wheeler—to give the Protagonist the run down on inversion.

In addition to needing his own air supply and bad handling when driving a car, if the Protagonist touches the forward version of himself they could be annihilated. Wheeler tries to hand the Protagonist a full, black body suit to prevent contact but the Protagonist says there isn't time. (Since he had just seen an inverted version of himself driving the car, he knew he shouldn't put on a suit.)

At the turnstile in the freeport in Oslo, the inverted Protagonist wears that full black body suit when he fights himself and that prevents the annihilation.